Assumptions and interventions about the so-called "obesity epidemic" pervade health and physical education classrooms and national policy agendas in New Zealand, as they do elsewhere in the Western world. In contrast, critical scholars in these subjects advocate an active deconstruction of the tenets and presumptions underpinning public and media conceptions of obesity, related body norms and physical activity and nutrition interventions. This article employs Bourdieu's notions of field, capital and habitus to argue that each of these approaches emanates from a different field of cultural production. Drawing on a critical ethnographic study of a low socioeconomic school in South Auckland, New Zealand, I also argue that acknowledging students' own cultural fields might offer a way forward. (Contains 2 notes.)